1. Field of the Invention
The present invention relates to a display device, and more particularly, to a head-up display device for vehicles.
2. Discussion of the Related Art
In order to transmit a large amount of text or image data, the demand for electronic display devices displaying video images, graphic characters, characters, etc. rapidly increases. Recently, an attempt to produce a mass of displays, which are handy to carry and realize a large-sized screen, is made. Further, portable personal display devices having a small size displays a large-sized screen, and head-up display (HUD) products, which are used during driving of a vehicle, requires a device having a compact constitution and realizing a large-sized screen.
While driving, a driver must observe articles coming in sight and check driving state of a vehicle (velocity, RPM, direction, etc.). Therefore, the necessity of a head-up display (hereinafter, referred to as “HUD”) as a medium for providing safety to the driver and effectively transmitting vehicle driving data and peripheral circumstantial data to the driver increases.
HUDs are systems, which provide vehicle driving data or other data in a range not deviating from the front of a driver, i.e., a main line of driver's sight, during driving of a vehicle or an airplane.
The HUDs in its early stage were developed with the object of being attached to an airplane, particularly a fighter to provide flying data to a pilot during flying. Devices, which were developed so as to apply this principle to vehicles, are HUDs for vehicles.
While a driver drives his/her vehicle at a velocity of approximately 100 km/h, the vehicle moves to a distance of approximately 55 m at the time (2 seconds) when a driver fixes his/her sight from a gauge cluster to a road, and thus may cause danger. One method for reducing this danger is the development of HUDs for vehicles. The HUDs for vehicles display data (velocity, distance covered, RPM, etc.) of a gauge cluster on a main line of driver's sight of a front glass window, such that the driver can easily get driving data during driving. Thereby, the driver perceives important driving data with keeping his/her eyes on the road, and thus performs safe driving.
Here, the above conventional HUD system has problems, as below.
FIG. 1 is a schematic view of a conventional HUD. As shown in FIG. 1, the conventional HUD includes a panel 10 for displaying driving data transmitted from an internal system of a vehicle, a fold mirror 20 for transmitting the driving data in a desired direction, a concave mirror 30 for reflecting and magnifying the driving data, and a wind shield 40 projecting for image data magnified by the concave mirror 30 to a driver, etc. Therefore, the conventional HUD creates a virtual image within the range of a driver's main visual field, and thus provides the driving data to the driver.
Therefore, the conventional HUD for creating the virtual image includes a large number of components for reflecting the driving data, thus increasing the volume of a HUD product and being high-priced. Further, the shaking of the reflected data is accumulated due to the vibration of a vehicle during driving, and thus the image quality of the HUD is deteriorated. Further, the conventional HUD cannot increase a magnifying power any more due to the limit in the volume of the product, and requires a cooling system so as to reduce the rise of the temperature when a large-sized panel is used, thereby causing a difficulty in obtaining reliability, and being high-priced.
Further, the conventional panel 10 has the resolution of a Video Graphics Array (VGA) grade, and displays driving data of the VGA grade in a visible region using the whole resolution, thus causing a problem of limiting the position of driver's eyes.
Accordingly, in order to obtain driving data through the above HUD, a driver must maintain his/her eyes to the fixed visible region.